Broken discharge valve on Vilter 456

[usgreg]

These compressors (2 high stage, 2 booster ) each have a "viltech" controller, so pressure, temperature and cycle timing are more accurately controlled, (no system PLC) and yes this does cycle off as I do not like to let them run for extended periods of time fully unloaded. Unloaded head temperature appears to build up in this mode. I have used a stethoscope on start up on each head and do not here anything unusual. It does not stay off for more than 2-4 minutes and has a drive for a soft start. controls for speed control have not been installed. Vilter has stated that they can go to as low as 50% speed (fully loaded) and maintain adequate oil pressure. Liquid trapping is possible, but I did not think it could happen in the 2-4 minutes of off time. The ammonia liquid for head/oil cooling is from the high temp recirculator and regulated down to feed each compressor. When you refer to a non-return valve, is that the same as a check valve? There is a high level safety on the recirculator as well.

[RANGER1]

These compressors (2 high stage, 2 booster ) each have a "viltech" controller, so pressure, temperature and cycle timing are more accurately controlled, (no system PLC) and yes this does cycle off as I do not like to let them run for extended periods of time fully unloaded. Unloaded head temperature appears to build up in this mode. I have used a stethoscope on start up on each head and do not here anything unusual. It does not stay off for more than 2-4 minutes and has a drive for a soft start. controls for speed control have not been installed. Vilter has stated that they can go to as low as 50% speed (fully loaded) and maintain adequate oil pressure. Liquid trapping is possible, but I did not think it could happen in the 2-4 minutes of off time. The ammonia liquid for head/oil cooling is from the high temp recirculator and regulated down to feed each compressor. When you refer to a non-return valve, is that the same as a check valve? There is a high level safety on the recirculator as well.

usgreg, yes check valve, but appears as you say not the problem, just trying to work through the possibilities.

The high level, does it work or tested recently, time delay?

Is there anytime level could be higher than normal in recirculator?

Does Vilter have any ideas, not sure do they have a help line to help narrow thing down.

Usually broken valve is liquid slugging, overheating or metal fatigue!
It's a pretty simple compressor so frustrating.

Maybe concentrate on that cylinder to eliminate damaged liner seat etc.
Oil pressure OK 45-50psi.
If you test unloaders while running, do amps change same on each cylinder bank?